They could let you delete deleted items permanently, like Dropbox does. Storing data you uploaded with no way to delete it does have privacy implications, since it may be looked at by people working there and could be a lot more sensitive than a cat photo.
I'd say a term that is more unfairly given a thumbs down is giving them a license to user content, since it's impractical to operate a user-generated content site without this.
I agree. But sometimes the copyright license conceded by the user goes way beyond what's needed for the service. Why do you give rights to sublicense and to transfer to Facebook or Twitter?
Partially necessary. And I completely agree with you. The licenses they demand are far broader than what they need, but that goes to the imbalance inherent in the relationship: big company with lots of money for lawyers versus some person just wanting to tell his friends what he had for lunch.
I'd say a term that is more unfairly given a thumbs down is giving them a license to user content, since it's impractical to operate a user-generated content site without this.